Effect of Friction on Dense Suspension Flows of Hard Particles

TL;DR

This study uses simulations to explore how particle friction influences dense suspension flows, revealing three flow regimes and identifying the dominant dissipation mechanisms near jamming.

Contribution

It systematically characterizes the impact of microscopic friction on suspension flow regimes and predicts flow behaviors using energy balance, validated by simulations.

Findings

Identifies three flow regimes: Frictionless, Frictional Sliding, and Rolling.

Shows sliding contact dominates dissipation at low viscous numbers.

Flow near jamming exhibits asymptotic behaviors depending on friction and viscous number.

Abstract

We use numerical simulations to study the effect of particle friction on suspension flows of non-Brownian hard particles. By systematically varying the microscopic friction coefficient $\mu_p$ and the viscous number $J$, we build a phase diagram that identifies three regimes of flow: Frictionless, Frictional Sliding, and Rolling. Using energy balance in flow, we predict relations between kinetic observables, confirmed by numerical simulations. For realistic friction coefficient and small viscous numbers (below $J\sim 10^{-3}$) we show that the dominating dissipative mechanism is sliding of frictional contacts, and we characterize asymptotic behaviors as jamming is approached. Outside this regime, our observations support that flow belongs to the universality class of frictionless particles. We discuss recent experiments in the context of our phase diagram.